At present, the single-cylinder filter sold on the market and used in various industries has disadvantages of large size, small filter area and low filter efficiency, and it has to be turned off before replacing its filter screen. Therefore, the continuous operation of the production is affected. The filter screen of a double-cylinder filter may be replaced when the double-cylinder filter is turned on, in contrast with the single-cylinder filter. However, the disadvantages of small effective filter area and low filter efficiency still exist if the filter screen is disposed on one side of the cylindrical surface where the inlet is located. Furthermore, in the operating process of the existing cylindrical filter, the material flow would form dead material somewhere, namely, material that is not moving. Such material cannot be timely removed, and affects the filtration effect and product quality.